DHA is important for oocyte maturation and successful fertilization
A: Number of eggs laid by WT (n=13), fat1 (n=10), and elovl2-/- (n=14) female zebrafish. B: Morphological and gross anatomical analysis of adult females on day after ovulation at 180 days post-fertilization (dpf). a–c: Morphology of WT, fat1, and elovl2-/- zebrafish. d–i: Overview of dissected ovaries from WT, fat1, and elovl2-/- zebrafish. Scale bar: 1 mm. C: GSI of WT (n=8), fat1 (n=7), and elovl2-/- (n=10) zebrafish on day after ovulation. D: Fatty acid composition (molecular percentage) of mature oocytes from WT, fat1, and elovl2-/-, n=4. E: H&E staining of WT, fat1, and elovl2-/- ovaries. Scale bar: 100 μm. F: Follicle quantification of WT, fat1, and elovl2-/- ovaries on day after ovulation, n=3. G: Representative images of embryos from natural mating of WT, elovl2-/-, and fat1 females with WT males. Scale bar: 1 mm. H: Comparison of fertilization ratio of groups in panel G. All values are mean±SD. Student’s t-tests were used in panels A, C, H. Multiple t-tests-one per row were used in panels D, F. *: P<0.05; **: P<0.01; ***: P<0.001. Arrows point to follicle cells at different developmental stages. PO: primary oocyte; PVO, previtellogenic oocyte; VO, vitellogenic oocyte; MO, mature oocyte. GSI, gonadosomatic index. H&E, hematoxylin-eosin.